In an electric storage device such as a secondary battery, heat generated by electrochemical reaction of storage cells arranged therein may build up, possibly increasing temperature. Power generation efficiency of the electric storage device possibly degrades when the device is heated to a high temperature. Therefore, temperature regulation is desirable.
Japanese Patent Laying-Open No. 2000-243370 discloses an assembled battery in which through holes are formed in partition walls of each battery cell in a battery case for electrically connecting electrodes of adjacent battery cells, and a heat conductive member formed of a material having superior electric conductivity and thermal conductivity is provided in the through holes. In the assembled battery, the heat-conducting member is sandwiched between two collector plate connectors that are in contact with cathode collector plate and anode collector plate. The heat-conducting member is formed to have a portion protrude outside the assembled battery, and a thermistor or the like is attached to the protruded portion, allowing detection of the temperature in the assembled battery.
Japanese Patent Laying-Open No. 10-55825 discloses a non-aqueous electrolytic secondary battery including a stacked electrode body having cathode and anode stacked with a separator inserted therebetween and a thermocouple wrapped therein. Opposite ends of the thermocouple are connected to a terminal for measuring internal temperature arranged on a surface of battery body. Voltage is measured by connecting a control circuit to the terminal for measuring internal temperature, and when the measurement goes out of a preset appropriate voltage range, charge/discharge is suppressed. According to the disclosure, the non-aqueous electrolytic secondary battery maximizes battery performance while attaining higher safety.
Japanese Patent Laying-Open No. 2004-253155 discloses a bipolar lithium ion secondary battery having a plurality of bipolar electrodes with cathode formed on one surface and anode formed on the other surface of a collector stacked in series, in which a portion of a periphery of the electrode is not insulated and the collector is exposed.
Japanese Patent Laying-Open No. 8-7926 discloses a non-aqueous electrolytic secondary battery comprised of a cathode using lithium compound as cathode active material, an anode using carbonaceous material in which lithium can be doped/undoped as an anode active material, and a non-aqueous electrolyte, in which a bipolar type electrode having cathode active material and anode active material held on opposite sides of one collector is used.
References described above disclose measurement of battery temperature by inserting a heat-conducting member in a battery case and by measuring the temperature of heat conducting member, or measurement of battery temperature by inserting a thermocouple to the central portion of a wound stacked body. In these batteries, however, the structures for measuring the battery temperature are complicated.